Case-shift mechanism



Aug. 23,1927. 1,640,127

J. F. KOCA' CASE SHIFT MECHANISM Filed Jan. 10, '1925 V GINVENTO/F:

Patented Aug. 23, 1927.

UNITED STATES PATENT OFFICE.

JAMES I. KOCA, OF WOODSTOCK, ILLINOIS, ASSIGNOR TO WOODSTOCK TYPEWRITERCOMPANY, OFYWOOIDSTOCK, ILLINOIS, A CORPORATION OF ILLINOIS.

CASE-SHIFT MECHANISM.

Application filed January This invention relates to case shift mechanismfor typwriters and is especially useful in connection with power driventypewriters such as that shown in the application of Otto A. Hokanson,Serial No. 732,-

615, filed August 18, 1924.

. The invention has for one of its objects the provision of case shiftmechanism which will permit the shiftablc member to be moved by a poweractuated drive and will retain the member in its shifted position solong as the shift key is held depressed.

A further object is to provide ease shift mechanism which shall be ofimprovedconstruction and operation.

The invention is exemplified in the combination and arran ement of partsshown in the accompanying drawing and described in the followingspecification, and it is more particularly pointed out in the appendedclaims.

In the drawing Fig. 1 is a vertical sectional view of a portion of atypewriter having one embodiment ofdthe present invention appliedthereto;

Fig. 2 is a fragmentary top plan view of a detail of construction.

- The numeral 10 designates a typewriter frame having a power driventoothed cylinder 11 journaled therein. A shift-lever 12'is pivoted at 13and carriesa contact device 14 arranged to engage a lug 15 on anactuator 16. The actuator 16 is pivotally 36 connected at 17 to .arocker 18 pivotally mounted at 19 on a cross-bar 20. When the lever 12is depressed the actuator 16 will be moving downwardly to bring acontact tooth 21 into engagement with the power drive 11. This'will movethe actuator 16 forwardly until its inclined surface 22 contacts wit anadjustable screw 23 mounted on a cross-bar 24. The contact between thecam face 22 and the screw 23, will disenga e the tooth 21 from the powerdrive 11. e spring'25 will then return the actuator 16 to its initialo'sition.

A link 26 is pivotally connected at 27 to the rocker 18 and has its rearend pivotally connectedat 28 to an arm 29 with the shift frame 30. Theshift frame 30 is pivotally mounted at31 on the typewriter frame 10. Anadjustable slid ng connection comprising a screw 32 and slots 33 permitsreturn movement of the rocker.

formed rigid- 10, 1925. Serial No. 1,530.

18' while the rear end ofthe link 26 is retained in its forwardpositionl Forward movement of the rocker will rotate the shift frame 30in a clockwise direction to shift the platen for upper case writing.Means is provided for retaining the platen in its upper position solongas the shift lever 12 is depressed. This retaining mechanism comprises astop 34 mounted on the shift frame 30 and a detent 35 having a shoulder36 thereonfor engaging the stop 34. The detent 35 is pivoted at 37 andis provided with a sprin 38 for normally urging the detent upwardly.When the shift frame is actuated by thepower mechanism the shoulder 36will snap into position behind the stop 34 and retain'the platen in itsuppermost position.

The forward end of the detent 35 in front of the shoulder 36 is slottedto receive a releasing dog 39 pivotally mounted at 40 in the slotted endof the detent. The dog 39 is provided with .a downwardly extending arm41 which is pivoted at 42 to a link 43. The link 43 is pivotallyconnected at 44 to an arm 45 formed integral with the shift lever 12 andextending upwardly therefrom. When the key lever is depressed the arm 45moves forwardly, thus rotating the release dog 39 in a clockwisedirection so as to bring ll the upper edge of the dog flush with.theupper face of the bifurcated portion of the detent 35. This permitsthe shoulder 36 to engage the stop 34 and so long as the shift lever isdepressed the shoulder 36 will hold 60 the shiftframe 30 in its u perposition irrespective of the action of t e power driven mechanism. Whenthe shift lever is released, however, the spring 46 will raise the shiftlever and move the arm 45 rearwardly which will rotate the release dog39 in a counter-clockwise direction and force the shoulder 36 out ofengagement with the stop 34. This will permit the platen to movedownwardly into its lower case position. In this we mechanism isprovided by means of whic the power for shifting the typewriter parts isfurnished by the power drive 11 but the arts will remain in theirshifted position so ong as the key is held depressed.

I claim v 1. Typewriter mechanism comprising a pivoted shift frame, astop mounted on said shift frame, a spring actuated detent having ashoulder for engaging said stop, a 110 release dog movably connected onsaid detent adjacent said shoulder for engaging said stop to disconnectsaid detent from said stop, a shift lever, and means for connecting saidshift lever with said dog.

'2. Typewriter mechanism comprising a shift frame, a power drive, anactuator for said shift frame, a shift lever for connecting saidactuator and power drive, a link for connecting said actuator and shiftframe arranged to permit return movement of said actuator independentlyof said shift frame, a detent for automatically retaining said shiftframe in its shifted position, and means controlled by said shift leverfor releasing said detent.

3. In a typewriter, a pivotally mounted shift frame having a stop membermounted thereon, a detent slidably engaging said stop member and havinga shoulder for engaging said stop member to retain said frame in shiftedposition, a shift key lever, a releasing dog pivotally mounted on saiddetent adjacent said shoulder and in position to engage said stopmember, and means connecting said dog with said shift key lever to forcesaid detent out of engagement with said stop member when said shift keylever is released.

'4. In a typewriter, a pivotally mounted shiftframe, a shift key lever,astop member carried by said shift frame, a detent having a shoulderthereon for engaging said stop member to retain said shift frame inshifted position, a spring for urging said shoulder into holdingrelation with said stop member when said frame is shifted, a bell cranklever mounted on said dedrive to effect case shift movement, a caseshift lever for moving said actuator into operative relation with saidpower drive,

means for automatically disconnecting said actuator from said powerdrive after a case shift movement is effected, a spring actuated detenthaving a shoulder thereon for retaining said shift frame in its shiftedposition, a release dog pivotally mounted on said detent adjacent saidshoulder, an arm projecting upwardly from said case shift lever, and'alink connecting said arm and release dog to release said detentwhen saidcase shiftlever is released.

In testimony whereof I have signed my name to this s ecification on this7th day of January, A. 1925.

JAMES F. KOCA

